"One way of thinking about the confinement problem was suggested by e+ e- annihilation into hadrons. Initially, the virtual photon dissociates into a quark and an antiquark that move with almost the speed of light back-to-back. Feynman had argued that additional pairs would be produced in the region between them, along the line separating the initially produced . The new pairs and original would rearrange and become a bunch of outgoing mesons [...].

Feynman's theory of the process was very simple. He would put his hands in front of his face, almost touching. Then he would quickly draw them apart. While doing this he would make a sound something like "Brrrrrrrrrp". I interpreted this to mean that each outgoing quark would radiate a pair, which would almost keep up with their parents. Then one of the newly produced quarks would made with its parent, producing a meson and leaving an unmated or . The unmated would still be moving out but with slightly less energy than the original pair. The whole thing would repeat itself until a low-energy pair would emerge at the center and form a final meson. I called this "the outside-inside cascade".

L.Susskind, "Quark Confinement", in "The Rise of the Standard Model", Cambridge University Press 1997.